Alpinia galanga (L.) Willd. (or greater galangal) and Alpinia conchigera Griff. (or lesser alpinia) belong to the Zingiberaceae (ginger family). The plants are native to Indonesia, Thailand, Malaysia and India. The rhizomes are used as a condiment in some areas. Alpinia galanga is traditionally used for the treatment of inflammatory conditions, respiratory infections, cancer, dyspepsia, colic, sea sickness and as a tonic, an aphrodisiac and an abortifacient.
The rhizomes of A. galanga and A. conchigera comprise several phenylpropanoids with pharmacological activity, including 1′S-1′-acetoxychavicol acetate (ACA, Galangal acetate, CAS #[52946-22-2]), 1′S-1′-acetoxyeugenol acetate (AEA), CAS # [53890-24-7] and 1′S-1′-hydroxychavicol acetate (HCA) CAS # [53580-61-3]. The rhizome also contains essential oils with 1,8-cineole being a major constituent. ACA has been reported to have numerous effects as a carcinogenesis inhibitor (Ohnishi et al., 1996), for the treatment of asthma in mice (Seo et al., 2013), as antiplasmid agent (WO07088408 A1), and in the treatment for HIV-1 infection (Ye and Li, 2006). Thus ACA may be an important active component of A. galanga. 
ACA is a semivolatile phenylpropanoid which is susceptible to evaporation and/or degradation in the course of preparation—especially under typical hydrolytic conditions in water or aqueous ethanol, in particular if raised temperatures are imposed on the extract (Yang and Eilerman, 1999). Under these conditions ACA may be partly or fully converted to 1-hydroxychavicol acetate and/or p-acetoxycinnamic alcohol and/or p-coumaryl diacetate (Yang and Eilerman, 1999). As a natural antioxidant, ACA is also susceptible to oxidative degradation.
When it comes to male fertility problems, there are two specific problems that tend to occur most often. The first of these is low sperm count. A low sperm count refers to a situation in which a man's semen does not contain a “normal” amount of sperm. A low sperm count is the most common fertility problem for men. After a low sperm count, however, the second most common fertility problem for men is low sperm motility. Low sperm motility refers to a situation in where enough of a man's sperm do not move forward. If the sperm do not move forward, they cannot make the journey from the vagina past the cervix towards the fallopian tubes, where they can fertilize an egg.
There are presently very few medical treatment options for low sperm count and/or low sperm motility, but A. galanga-based compositions in general and ACA in particular have for many years been associated with a large variety of pharmacological effects, amongst these recently published results on the effect of a combined pomegranate/galangal-preparation (Punalpin®) on reduced sperm quality in a randomized, placebo-controlled, double-blinded trial. Seventy men with reduced sperm quality were randomized to take tablets containing 1) standardized amounts of rhizome of greater galangal (corresponding to 16 mg 1'S-1′-acetoxychavicol acetate/day) and extract of pomegranate fruit or 2) placebo daily for three months. From baseline to after three months of treatment, the average total number of motile sperm increased with 62% (from 23.4 millions to 37.8 millions) in the pomegranate/galangal-group, while for the placebo group the number of motile sperm increased with 20% (from 19.9 millions to 23.9 millions). The increase in total motile sperm count in the pomegranate/galangal-group was significantly higher than in the placebo group (p=0.026) (Fedder et al., 2014).
A statistical significant improvement of sperm quality, in particular sperm motility (p<0.01) and sperm count (p<0.05), has also been reported in healthy mice fed with extract of A. galanga (Qureshi et al., 1992). Thus, there is supportive evidence that A. galanga-preparations improve sperm motility in mammals.
One possible causative explanation for the beneficial effect of A. galanga-preparations on sperm motility is the role of ACA as an antioxidant, more specifically as a superoxide generation inhibitor (Nakamura et al., 1998).
Oxidative stress results from an imbalance between the production of reactive oxygen species (ROS), such as superoxide anion (O2−) and their metabolism, for example, by superoxide dismutase (SOD). Oxidative stress has been shown to exert detrimental effects on sperm quality. ROS-mediated damage to sperm is a significant contributing factor in 30-80% of cases of male infertility. ROS cause infertility by two principal mechanisms. First, ROS damage the sperm membrane, which in turn reduces the sperm's motility and ability to fuse with the oocyte. Secondly, ROS directly damage sperm DNA, compromising the paternal genomic contribution to the embryo (Tremellen 2008).
Another sperm quality-enhancing effect of A. galanga relates to testosterone production. A sufficiently high level of testosterone in testis is a prerequisite for male fertility and normal spermatogenesis. The testosterone level in serum increased in rats fed with extract of A. galanga (p<0.05) (Islam et al., 2000). Furthermore, the number of red blood cells increased in mice fed with extract of A. galanga (p<0.05) (Qureshi et al., 1992). The latter effect on red blood cell level may be due to an increase in testosterone production. Testosterone and related androgenic derivatives are known as potent stimulators of red blood cell formation (erythropoiesis).
Alpinia galanga-preparations have also been shown to reduce blood glucose in healthy (Akhtar et al., 2002) as well as in diabetic animals (Srividya et al., 2011). Interestingly, diabetes is associated with reduced sperm quality, more specifically increased sperm nuclear and mtDNA damage (Agbaje et al., 2007).
The physiological mechanism behind the effect of A. galanga on diabetes has not been determined yet. It may be due to galangin, an antioxidant flavonol present in high concentrations in the rhizomes. The effect of galangin on whole-body insulin resistance and kidney oxidative stress was examined in a fructose-induced rat model of metabolic syndrome (Sivakumar et al., 2010). Galangin dose-dependently normalized blood glucose and insulin levels, and maintained oxidant-antioxidant balance.
Metabolic syndrome is also associated with reduced sperm quality, expressed as reductions in sperm concentration, total sperm count, total motility, sperm vitality, mitochondrial membrane potential, free testosterone and free progesterone, while values for DNA fragmentation increase (Leisegang et al., 2014). Other symptoms of metabolic syndrome are abdominal obesity, high levels of triglycerides in serum, elevated blood pressure, elevated fasting plasma glucose and low high-density lipoprotein (HDL) levels.
Apart from the abovementioned properties of Alpinia galanga-preparations regarding improvement of sperm motility, enhancement of testosterone level and reduction of blood glucose level, other studies report on reduction of serum triglycerides (Srividya et al., 2011; Iyer et al., 2013), enhancement of HDL levels (Iyer et al., 2013) and inhibition of increase in body weight (Kumar et al., 2011). The general anti-hyperlipidemic activity is possibly caused by the heterocyclic aldehyde, hydroxymethylfurfural (Iyer et al., 2013) and the flavonol galangin (Kumar et al., 2013). All these effects of A. galanga-preparations are well-suited to alleviate the symptoms of metabolic syndrome.
Up to date, A. galanga-based compositions or preparations have been obtained by ethanol or methanol extraction and have shown variable and relatively low contents in ACA, which can be explained either by co-evaporation of ACA with the extraction solvent during workup or by heat-induced decomposition. This has been confirmed by the inventors of the present invention, as the analysis of a number of dry A. galanga extracts sold as raw material for food supplements showed very low or no ACA content in the products analyzed. The ACA content in fresh rhizomes is relatively high (up to 11% DW). It is therefore possible that the considerable, or in some cases, total, loss of ACA in the final product, may be caused by either 1) one or more of the methodological steps converting the fresh rhizomes to dry powders suitable for incorporation in tablets, and/or 2) loss during storage prior to or after the preparation of the dry extracts or tablets.
Although ACA is thought to be an important active component of A. galanga, it is possible that also other components of A. galanga or A. conchigera are responsible for the various pharmacological activities referred to above. It is, however, for obvious reasons not feasible to employ fresh rhizomes of A. galanga or A. conchigera in daily practice. An orally ingestible dosage (eg tablet) form of A. galanga and/or A. conchigera with a predictable content of phenylpropanoids, notably ACA, and other key components is clearly preferable.
The inventors of the present invention in the co-pending international application PCT/EP2014/061880, which is hereby incorporated by reference in its entirety, have described how a dry preparation of rhizomes from A. galanga or A. conchigera can be produced by freeze-drying said rhizomes, followed by pulverizing the dry plant material. The resulting dry preparation contains substantially all the constituent parts of said rhizomes in dry (ie. desiccated) form, including a high content of ACA.
Subsequent work with this dry preparation has however shown that it is not well-suited for preparing orally ingestible dosage forms of A. galanga or A. conchigera with a high content of ACA, which was the original intention. Firstly, the dry preparation as prepared in PCT/EP2014/061880 has been found to be quite heterogeneous since the fibers of the rhizome have a different density and structure than the remainder components produced by the milling process. It was not possible to incorporate this inhomogeneous mixture of light fibers and heavier components evenly into tablets, i.e., the first tablets produced would have a higher proportion of the heavier fragments compared to those produced at the end of the tablet production process because the smaller and heavier fragments would move to the bottom of the funnel feeding the material into the tablet machine.
Secondly, the large surface area of the pulverized material rendered it susceptible to microbial contamination and at the same time facilitated the evaporation of the volatile compounds originally contained in the rhizomes, including ACA. These factors overall led to a poor stability and shelf life of the bulk material.
Thirdly, as described in PCT/EP2014/061880, in order to prevent microbial contamination of the product, the dry preparation had to undergo a complicated procedure involving heating in airtight bags, and finally, the dry preparation eventually proved very difficult to handle in tablet production due to its poor flowability but especially due to the presence of fine, highly irritant plant fibres which filled the air during handling of the dry preparation, and necessitated the use of ski goggles to prevent eye problems for the operators.
Thus there remains a need for a method for producing a preparation of A. galanga and/or A. conchigera which not only comprises all the compounds assumed or reported to have pharmacological activity in the original rhizome(s), including a high content of ACA, but also is well suited for pharmaceutical formulation.